Electrical connector for printed circuit boards



Dec. 18, 1962 P. GRECO ELECTRICAL CONNECTOR FOR PRINTED CIRCUIT BOARDS Filed March 23, 1959 Z5" 35 fi 2 Sheets-Sheet 1.

V 1- I H62 4 INVENTOR. 2 52. 560

BY I

Dec. 18, 1962 P. GRECO 3,069,652

ELECTRICAL CONNECTOR FOR PRINTED CIRCUIT BOARDS Filed March 23, 1959 2 Sheets-Sheet 2 INVENTOR. Pre Geaa BY wzf United States Patent ()filice Fatented Dec. 18, 9'62 This invention relates to electrical connectors and, more particularly, to electrical connectors for connection to one or more electrically conducting surfaces on one or more faces of a printed wiring board.

In recent years printed circuit or Wiring boards for mounting and interconnecting electrical components have been widely used in the electronic art. Such boards have, in general, been manufactured with the printed wires terminating in aligned parallel arrangement along one edge to form a terminal strip. This edge containing the aligned termination of the printed wiring is generally used as the plug portion of a connector and inserted into a circuit receptacle which may comprise an array of spring members mounted in a suitable housing. Connection to the remainder of the circuit is then accomplished by connecting a conductor to the spring contact members externally by a variety of means such as crimping, indenting, soldering or wrapping the wire to the terminal of the spring contact.

in order to assure proper contact between the connector spring and the plug board, the finger or spring contact has generally been pretensioned, which causes considerable wear in the thin foil conductors of the printed circuit boards due to the high insertion forces necessary to complete the connection. When the spring contact pressure is red ced to affect a corresponding reduction in the wear on the printed circuit board, a poor electrical contact often results. These conflicting requirements of reduced spring contact pressure to minimize wear and increased spring contact pressure for better electrical characteristics have resulted in compromises which often were unsatisfactory.

The spring contact member has in the past generally been permanently mounted in the receptacle housing. Thus the failure of a single contact has necessitated the scrapping of the entire receptacle. It has been long recognized that it would be desirable to have a receptacle in which the individual spring contacts could be inserted into and removed from the receptacle independent of the other contacts. This would allow the attachment of the contact to a wire prior to its insertion into the receptacle. Moreover, it would allow the removal and replacement of individual contacts.

However, it has also been recognized that a removable contact must be capable of withstanding forces such as pulling on the attached wire which tends to accidentally remove the contact from the housing. Merely using a struck-up portion of the contact as a stop to resist accidental removal has not been entirely satisfactory because such a portion can be deformed quite easily.

One of the objects of this invention, therefore, is to provide a simple and inexpensive type of connector for making electrical connections to one or more electrically conducting strips on one or more faces of a printed circuit board in which each spring contact is resiliently biased without overstressing the contacted strip.

Another object of this invention is to provide an electrical connector for making multiple contacts to the wiring on a printed circuit board in which each of the contact members of the connector may be individually and readily removed from the receptacle.

Another object of this invention is to provide an electrical connector of this type in which the spring contact member is resiliently biased by a simple and inexpensive means.

Still a further object of this invention is to provide an electrical connector of this type in which each of the contact members is positively locked to the housing to prevent movement in either direction of the contact and which is capable of resisting relatively high forces tending to accidentally remove the contact.

in one embodiment of thi invention an electrical con nector is provided in which a receptacle body has an elongated aperture with a plurality of slots therein. Each of the slots includes a groove having a projection disposed in it, which forms a front locking shoulder. A rear locking shoulder is also associated with each of the slots. A spring contact member is inserted into and supported by the sides of the slot and includes a resilient reinforcing portion and a resilient contact portion which extend into the groove portion of this slot. An opening is provided in the contact member which receives the projection in the groove to lock the contact member against Withdrawal and a struck-up portion is also provided which co-acts with the rear shoulder to prevent overinsertion of the contact member and properly locate the contact member within the slot.

Another feature of this invention is the use of the contact member which may be punched from strip material in a simple and economical manufacturing process.

These and other objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view of the electrical contact used in a connector of this invention;

FIG. 2 is a side view in elevation of the contact member shown in FIG. 1;

FIG. 3 is a side view in cross section of the electrical connector of this invention showing a pair of contact members inserted therein;

FIG. 4 is a perspective view partly in cross-section of the electrical connector of this invention showing a co n tact member inserted therein;

FIG. 5 is a front elevational view of the electrical con-- nector of this invention;

FIG. 6 is a partial view in perspective showing a printed circuit board and electric connector of this invention prior to connection;

FIG. 7 is a cross-sectional view showing the indexing means for the electrical connector of this invention; and

FIG. 8 is a cross-sectional view illustrating the shape of the central passageway taken between the bottom of the printed circuit board receiving slot and the rear locking shoulder.

Referring to FIGS. 1 and 2 of the drawing, an electrical contact member for use in the connector of this invention is therein shown to comprise a contacting portion 10, a support portion 12 and a wire attaching portion 14. The wire attaching portion 14 comprises a U-shaped inaoeacee sulation shroud or insulation grip l6 and a wire gripping section 13. The U-shaped shroud grip and wire grip 16 and 13 are crim'ped about an electrical wire as hereinafter explained.

I The longitudinally extending support portion 12 of the electrical contact member is made from sheet metal stock from which a rear locking finger 2th is formed or struck up. The support portion 12 is terminated by out- 'wardly projecting integral arms 21a and 21b, which, together with the end bridge portion 23 joining the arms 21a and 21b, defines a slot 25. A resilient reinforcing finger 24 is attached to one end of the support portion 12 and has a free end portion normally projecting away than the Width of the support portion 12. The ocntact is terminated by a contact finger 22 having a Width less than the width of the support portion 12. The contact finger 22 is bent back on itself as shown in FIG. 2, and the reinforcing finger 24 has its free end in abutting relation thereto providing a resilient reinforcement or bias against deformation of the contact finger 22. The slot defined by arms 21a and 21b and bridge 23 form a front locking shoulder 26.

As shown in FIGS. 3-5 and 8, the electrical conmotor of this invention includes an insulating housing or receptacle 28 of plastic or other suitable insulating material, body being defined by parallel upper and lower eans 27 joined at their ends by parallel side walls '29. The walls 27 have at spaced intervals inwardly projecting separating ribs 31 defining slots 32 which 'are arranged in opposed relationship to each other. Each slot 32 includes a groove 34. Located Within each groove 34- is a projection on sloped toward the rear of the housing forming the front ldcking shoulder 38 which coacts with the slot oil the contact member. I An electrical conductor 46 has its insulation 42 stripped back from the wire 44 a given distance and the electrieal contact member 12 shown in FIGS. 1 and 2 then has its shroud gripping portion 16 crimped about the electrical insulation 42 and its Wire gripping portion 18 crimp ed about the conductor 44 to form a mechanical and electrical connection to the conductor 40. The contact member 12 is then inserted into the slot 32. The "contact finger 22 extends into the groove 34 and the contact fii'e'rnber 12 is supported by the shoulders of the groove 32 allowing the contact finger 22 freedom to flex within the groove. Thus the groove 34 and the space above the shoulders 32 form a T shaped opening as shown in FlGURES 4 and 3 of the drawing. The contact member 12 is inserted until the rear locking finger 2t) abuts the rear locking shoulder 46 and prevents further insertion. At this point the front locking shoulder 26 of the slot fits over the ramp projection 38 in the groove "4- to prevent the withdrawal of the contact. Wire-i1 it is desired to withdraw the contact from the housing 28, it is merely necessary to disengage the front locking shoulder 26 from the projection 38.

Referring to FIGS. 6 and 7 of the drawing, it is clear that to make the proper circuit connections, the printed circuit board 45 must be properly oriented within the connector housing 28. The printed circuit board 48 is depicted with a terminal strip 49 designed, when properly oriented, to make contact with contact member 51. To provide for this orientation a slot 5% is cut in the circuit board &8, and an orienting stub 52 is located in predetermined slots of the housing 28. The orienting device 52 is a U-shaped member having locking slots 56 and 58 cut out of its top and bottom arms. These locking slots co-act with the projections 38 in each of the top and bottom grooves 34 of the housing to retain the U-shaped member 52 therein and to thus provide the proper orientation.

7 While specific embodiments of this invention have been shown and described, it will be understood that they are illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention.

lclaim:

1. An electrical connector for a printed circuit board comprising: an insulating housing having a front and a rear face and a plurality of spaced apart, parallel, contact receiving bores therethrough from face to face, and a transverse, printed circuit board receiving slot into said front face intersecting the forward part of each of said bores; each of said bores having a constriction formed therein, and an upstanding projection formed in said forward bore part; an electrical contact of conductive metal disposed in each of said bores, each of said contacts including a relatively fiat body portion, slot defining arms integrally extending from said body portion, means joining the distal ends of said arms closing said slot, a first resilient finger having a proximal end integrally depending with a reverse bend from said slot closing means and having a distal mating contact errgaging end which is disposed in said transverse slot, a second resilient finger having a proximal end integrally depending from said body portion and having a distal end abutting a surface of said first finger to bias said first finger distal end away from said fiat body portion, said first and second fingers being transversely centered with respect to said fiat body portion and of a width less than said flat body portion to provide a pair of margins of flat body portion which extend beyond said fingers, and a third finger struck up from said fiat body portion and longitudinally spaced from said first and second fingers; said bore constriction having a central passageway of substantially T shape, the leg of the T being adapted to pass said first and second fingers while the cross of the T is adapted to pass said flat body portion, the ends of the cross interlocking with said pair of margins to prevent transverse movement of said contact; whereby each said contact may be inserted from said housing rear face into said respective bore, through said T shaped constriction, said slot closing means snapping over said forward bore projection to abut therewith, said first finger distal mating contact engaging end being disposed in said transverse slot, and said third finger engaging the rear of said bore constriction to prevent overinsertion of said contact; and whereby each said contact may be released from said respective bore by deflecting said slot closing means away from said forward bore constriction.

2. An, electrical connector for a printed circuit board comprising: an insulating housing having a front and a rear face and a plurality of spaced apart, parallel, contact receiving bores therethrough from face to face, a transverse, printed circuit board receiving slot into said front face intersecting the forward part of each of said bores, and each of said bores having a constriction formed therein; an electrical contact of conductive metal disposed in each of said bores, each of said contacts including a relatively fiat body, a first interlock means integral with the forward portion of said contact body, a first resilient finger having a proximal end integrally depending from said first interlock means and having a distal mating contact engaging end which is disposed in said transver e slot, a second resilient finger having a proximal end integrally depending from said body portion and having a distal end abutting a surface of said first finger to bias said first finger distal end away from said fiat body portion, said first and second fingers being transversely centered with respect to said fiat body portion and of a Width less than said fiat body portion to provide a pair of margins of fiat body portion which extend beyond said fingers and a second interlock means integrally formed on said fiat body portion and longitudinally spaced from said first and second fingers;- said bore constriction having a central passageway of substantially T shape, the leg of the T being adapted to pass said first and second fingers while the cross of the T is adapted to pass said fiat body portion and said first interlock means, the ends of the cross interlocking with said pair of margins to prevent transverse movement of said contact, and a first and second bore interlock means; whereby each said contact may be inserted from said housing rear face into said respective bore, through said T shaped constriction, said contact first interlocking means snap looking into interlock with 5 said bore first interlock means to prevent removal of said contact from said bore, and said second interlock means engaging said bore second interlock means to prevent overinsertion of said contact; and whereby each said contact may be released from said respective bore by dis- 10 engaging said contact first and bore first interlocking means.

References Cited in the file of this patent UNITED STATES PATENTS Nero June 26, 1917 Chirelstein Oct. 28, 1941 Benham et al. Aug. 31, 1954 Collins et al. 1. Apr. 17, 1956 Jackson et al. Sept. 23, 1958 Gilbert Feb. 24, 1959 Mason Apr. 14, 1959 DAmico Sept. 1, 1959 Burtt ct al. Sept. 15, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF QOHREC'HUN Patent N00 3 O69 6S2 December 18 1962 Peter Greco It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.a

Column 3 line l4 for than the width read rm from the surface same line 14 for "'ocntact read contact as Signed and sealed this 18th day of June 19630 (SEAL) Attest:

ERNEST w. SWIDER DAVID L LADD Attesting Officer Commissioner of Patents 

